见英汉化学化工词汇。
水从凉水塔顶上自由落下，塔上设有排风扇通风以达到使水冷却的目的。

--------------------------------------------------
Note added at 5 hrs (2006-05-01 14:52:00 GMT)
--------------------------------------------------

英汉炼油辞典称其为诱导通风式凉水塔，引风式凉水塔。
induced draft-type 是相对于 forced draft-type. 前者是往塔外抽风，后者是往塔里鼓风。

forced draft-type cooling towers 称为强制通风式凉水塔。


--------------------------------------------------
Note added at 13 hrs (2006-05-01 23:05:38 GMT)
--------------------------------------------------

See the figure of an induced draft cooling tower at: http://www.tpub.com/content/doe/h1018v2/css/h1018v2_101.htm

"Induced draft cooling towers, illustrated in Figure 11, are constructed such that the incoming circulating water is dispersed throughout the cooling tower via a spray header. The spray is directed down over baffles that are designed to maximize the contact between water and air. The air is drawn through the baffled area by large circulating fans and causes the evaporation and the cooling of the water."